Study on the width of plastic zone of coal pillar along goaf in extra-thick coal seam

In order to solve the problem of surrounding rock stability in gob-side excavation under the condition of extra-thick coal seam and the reasonable width of coal pillar in excavation roadway, taking 4203 extra-thick coal seam working face of Jianxin Coal Mine as the engineering background, and the stress equation of limit equilibrium zone is established, and the distribution characteristics of lateral supporting stress of coal pillar under the condition of different width of coal pillar are obtained.By analyzing the plastic zone width of side coal pillar in goaf and roadway, the reasonable reserved width of coal pillar in goaf driving roadway under extra-thick coal seam condition is obtained.The results show that the gob side plastic zone width is 2.58 m, side of coal pillar width of plastic zone is 2.61 m, and analysis the coal core bearing zone under the condition of different coal pillar width, with the increase of and coal pillar width is constantly expanding, the concentrated stress area also increase, ultimately determine the special thick coal seam roadway driving along goaf under the condition of reasonable coal pillar width is 10 m.It can be seen from this that the integrity of the coal body is good, the stability of the surrounding rock of the roadway can be controlled, and good support effect has been achieved.